--- /dev/null
+/*
+ * probes/lttng-uprobes.c
+ *
+ * LTTng uprobes integration module.
+ *
+ * Copyright (C) 2013 Yannick Brosseau <yannick.brosseau@gmail.com>
+ * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; only
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <linux/fdtable.h>
+#include <linux/module.h>
+#include <linux/namei.h>
+#include <linux/slab.h>
+#include <lttng-events.h>
+#include <lttng-tracer.h>
+#include <wrapper/irqflags.h>
+#include <wrapper/ringbuffer/frontend_types.h>
+#include <wrapper/uprobes.h>
+#include <wrapper/vmalloc.h>
+
+static
+int lttng_uprobes_handler_pre(struct uprobe_consumer *uc, struct pt_regs *regs)
+{
+ struct lttng_event *event =
+ container_of(uc, struct lttng_event, u.uprobe.up_consumer);
+ struct lttng_probe_ctx lttng_probe_ctx = {
+ .event = event,
+ .interruptible = !lttng_regs_irqs_disabled(regs),
+ };
+ struct lttng_channel *chan = event->chan;
+ struct lib_ring_buffer_ctx ctx;
+ int ret;
+
+ struct {
+ unsigned long ip;
+ } payload;
+
+ if (unlikely(!ACCESS_ONCE(chan->session->active)))
+ return 0;
+ if (unlikely(!ACCESS_ONCE(chan->enabled)))
+ return 0;
+ if (unlikely(!ACCESS_ONCE(event->enabled)))
+ return 0;
+
+ lib_ring_buffer_ctx_init(&ctx, chan->chan, <tng_probe_ctx,
+ sizeof(payload), lttng_alignof(payload), -1);
+
+ ret = chan->ops->event_reserve(&ctx, event->id);
+ if (ret < 0)
+ return 0;
+
+ /* Event payload. */
+ payload.ip = regs->ip;
+ lib_ring_buffer_align_ctx(&ctx, lttng_alignof(payload));
+ chan->ops->event_write(&ctx, &payload, sizeof(payload));
+ chan->ops->event_commit(&ctx);
+ return 0;
+}
+
+/*
+ * Create event description.
+ */
+static
+int lttng_create_uprobe_event(const char *name, struct lttng_event *event)
+{
+ struct lttng_event_desc *desc;
+ struct lttng_event_field *fields;
+ int ret;
+
+ desc = kzalloc(sizeof(*event->desc), GFP_KERNEL);
+ if (!desc)
+ return -ENOMEM;
+ desc->name = kstrdup(name, GFP_KERNEL);
+ if (!desc->name) {
+ ret = -ENOMEM;
+ goto error_str;
+ }
+
+ desc->nr_fields = 1;
+ desc->fields = fields =
+ kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL);
+
+ if (!desc->fields) {
+ ret = -ENOMEM;
+ goto error_fields;
+ }
+ fields[0].name = "ip";
+ fields[0].type.atype = atype_integer;
+ fields[0].type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT;
+ fields[0].type.u.basic.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT;
+ fields[0].type.u.basic.integer.signedness = lttng_is_signed_type(unsigned long);
+ fields[0].type.u.basic.integer.reverse_byte_order = 0;
+ fields[0].type.u.basic.integer.base = 16;
+ fields[0].type.u.basic.integer.encoding = lttng_encode_none;
+
+ desc->owner = THIS_MODULE;
+ event->desc = desc;
+
+ return 0;
+
+error_fields:
+ kfree(desc->name);
+error_str:
+ kfree(desc);
+ return ret;
+}
+
+int lttng_uprobes_register(const char *name,
+ const char *path_name,
+ uint64_t offset,
+ struct lttng_event *event)
+{
+ int ret;
+
+ /* Shoudl we fail if the path is empty, it should be checked before */
+ if (path_name[0] == '\0')
+ path_name = NULL;
+
+ ret = lttng_create_uprobe_event(name, event);
+ if (ret)
+ goto error;
+
+ memset(&event->u.uprobe.up_consumer, 0,
+ sizeof(event->u.uprobe.up_consumer));
+
+ event->u.uprobe.up_consumer.handler = lttng_uprobes_handler_pre;
+ if (path_name) {
+ struct path path;
+ ret = kern_path(path_name, LOOKUP_FOLLOW, &path);
+ if (ret)
+ goto path_error;
+
+ event->u.uprobe.inode = igrab(path.dentry->d_inode);
+ }
+ event->u.uprobe.offset = offset;
+
+ /* Ensure the memory we just allocated don't trigger page faults. */
+ wrapper_vmalloc_sync_all();
+ printk(KERN_WARNING "Registering probe on inode %lu and offset %llu\n", event->u.uprobe.inode->i_ino, event->u.uprobe.offset);
+ ret = wrapper_uprobe_register(event->u.uprobe.inode,
+ event->u.uprobe.offset,
+ &event->u.uprobe.up_consumer);
+ if (ret) {
+ printk(KERN_WARNING "Error registering probe on inode %lu "
+ "and offset %llu\n", event->u.uprobe.inode->i_ino,
+ event->u.uprobe.offset);
+ goto register_error;
+ }
+ return 0;
+
+register_error:
+ iput(event->u.uprobe.inode);
+path_error:
+ kfree(event->desc->name);
+ kfree(event->desc);
+error:
+ return ret;
+}
+EXPORT_SYMBOL_GPL(lttng_uprobes_register);
+
+void lttng_uprobes_unregister(struct lttng_event *event)
+{
+ wrapper_uprobe_unregister(event->u.uprobe.inode,
+ event->u.uprobe.offset,
+ &event->u.uprobe.up_consumer);
+}
+EXPORT_SYMBOL_GPL(lttng_uprobes_unregister);
+
+void lttng_uprobes_destroy_private(struct lttng_event *event)
+{
+ iput(event->u.uprobe.inode);
+ kfree(event->desc->name);
+ kfree(event->desc);
+}
+EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_private);
+
+MODULE_LICENSE("GPL and additional rights");
+MODULE_AUTHOR("Yannick Brosseau");
+MODULE_DESCRIPTION("Linux Trace Toolkit Uprobes Support");
projects / lttng-modules.git / blobdiff